Centrifugal pump



1964 D. E. SINGELMANN 1 CENTRIFUGAL PUMP Filed April 28, 1960 6 Sheets-Sheet 2 INVENTCR. DIE TR/Cl-l E S/NGEL MA NN l 43 @M, M, W 3 @dd,

ATTORNEYS.

Feb. 11, 1964 D. E. SINGELMANN 3,120,813

CENTRIFUGAL PUMP Filed April 28, 1960 6 Sheets-Sheet 5 HODOGRAPH 0F m4 TER PART/CL E15 LEA v/Nc; rue INDUCER a/v THE/R WAY TOWARD THE MA nv IMPELL ER (RE-z. AT/VE TO THE MOVING lMPEL 1.51?)

IN VEN TOR.

OIETR/CH E S/NGELMANN A TTORNEYS.

D. E. SIN GELMANN CENTRIFUGAL PUMP Feb. 11, 1964 6 SheetsSheet 4 Filed April 28. 1960 INVENTOR.

0/5 TR/CH E. S/A/GEL MANN A TTORNEYS.

1964 D. E. SINGELMANN 3,120,813

CENTRIFUGAL PUMP Filed April 28. 1960 6 Sheets-Sheet 5 INVENTOR.

11117-0 9 D/ETgfQV E. S/NGEL III/IANN @M, W x @Z%,

ATTORNEYS.

1964 D. E. SINGELMANN 3,120,313

UUUUUUUUUUUUU MP D/ErRIc'H E S/NGEL MA N/V BY. 6W, M, gm,

ATTORNEYS.

United States Patent M 3,120,813 CENTREFIJGAL PUMP Dietrich E. Singelinann, l uifnio, N.Y., assiguor to llell Aircraft Corporation, Wheatiield, NY. Filed Apr. 28, 1960, Ser. No. 25,254 2 Claims. (El. 103-115) This invention relates in general to turbo-pumps and pertains more particularly to certain improvements in the over-all construction and internal details thereof.

Certain aspects of the present invention relate to the improvement of the construction and arrangement of component parts in a turbo-pump so as to render the same dimensionally small while at the same time highly eflicient and of high capacity particularly in relation to the size involved. Other aspects of the present invention relate to certain improvements in the internal details of turbo-pumps and, more particularly, to improvements relating to the design of inducers utilized in conjunction with a centrifugal pump assembly.

It has been known for some time that the use of inducer fins or blades in conjunction with the impeller blades of a centrifugal pump will vastly increase the capacity and efficiency of such type of pumps, mainly by virtue of the fact of permitting such pumps to operate at much higher angular velocities without cavitation which would normally be expected from pumps of more conventional design. There is a definite need for a pump of this type which is characterized by a high capacity and which at the same time is dimensionally small and consequently of light weight, and it is to these ends that the present invention is directed. For example, the present invention is characterized by a pump unit of extremely compact, dimensionally small and light weight construction, particularly wherein the component parts thereof are housed within a relatively small unit in such compact fashion as to be fitted for diverse usage. For example, a pump constructed in accordance with the present invention is admirably suited for use as a deep well pump where dimensional characteristics are extremely critical. Additionally, pumps constructed in accordance with the present invention are particularly well adapted for atomic reactors for charging the same or for boiler feed pumps.

In addition to the above, the present invention is characterized by the provision of certain improvements in the inducer blade construction, rendering the pumps more efiicient and of greater capacity and capable of operating at higher rotational speeds and, in addition thereto, the present invention is directed to certain improvements in the combination effected between the inducer blades and the impeller blades of centrifugal pumps achieving a definite cooperation between the inducer and impeller blades to the end of increasing the efficiency and permitting of higher capacity at higher rotational speeds than has heretofore been thought possible.

With the above, and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims, and the several views illustrated in the accompanying drawings.

FIGURE 1 is a sectional view taken through a pump constructed in accordance with the present invention and showing the details of internal construction thereof;

FIGURE 2 is a transverse sectional view taken substantially along the plane of section line IIII in FIGURE 1, showing details of the pump construction as well as the outlet means therefor;

FIGURE 3 is an enlarged fragmentary view showing the relationship between the inducer and impeller blades of the pump;

FIGURE 4 is a chart illustrating certain velocity char- 3,lZ,8l3 Patented Feb. 11, 1954 faicteristics imparted to the fluid by the inducer blades or FIGURE 5 is a plan View of an inducer-impeller assemblage of a modified form of construction;

FIGURE 6 is a sectional view taken substantially along the plane of section line VI-VI in FIGURE 5 illustrating further details of this modification;

FIGURE 7 is a partial plan view similar to FIGURE 5, but showing a further modified form of impeller-inducer assemblage;

FIGURE 8 is a sectional view taken substantially along the plane of section line VIII-VIII in FIGURE 7, showing further details of the secondary modification;

FIGURE 9 is an enlarged sectional view taken substantially along the plane of section line IXIX in FIGURE 8, showing further details of the inducer blades;

FIGURE 10 is a view similar to FIGURES 5 and 7, but showing a still further modified form of impellerinducer construction; and

FIGURE 11 is a sectional view taken substantially along the plane of section line XI-XI in FIGURE 10, showing further details of the modification. illustrated in FIGURE 10.

The arrangement of the component parts in accordance with the present invention wherein the pump and turbine unit is characterized by its extreme compactness and di mensionall small characteristics is best illustrated in FIG- URE 1 of the drawings. In this figure, the turbine end of the unit is indicated generally by the reference character 1d, whereas the pump portion of the unit is indicated generally by the reference character 11. The unit itself includes a stationary pump body portion 12 having a discharge passageway or involute 13 therein having the tangentially directed discharge portion 14, as is conventional and common with centrifugal pumps. One side of the body 12 is provided with a counterbore 15 receiving a machined shoulder portion 16 of the end body piece 17, and the opposite side of the body 12 is provided with a similar counterbore 18 receiving the shoulder 19 of the end body piece 20. The central portion of the body piece 17 is provided with a bore 21 through which the upper end portion 22, of a drive shaft indicated generally by the reference character 23 passes, and the outer face of this body portion 17 is provided with a counterbore 25 providing a seat for the outer race as of a ball bearing by means of which the end 22 of the shaft 23 is rotatably supported. The opposite end of the shaft 2-3, designated by the reference character Z7, is rotatably supported by a ball bearing 28 seated within a counterbore 29 in the hub portion Ell of cover plate 31. The cover plate 31 fits snugly within a counterbore 32 in the outer face of the body portion 24} and its cylindrical portion 33 is snugly fitted within a suitable bore 34 in body piece 28, substantially as is shown. An end plug 35 is fittedly engaged in the end plate 31 sealing off the end of the shaft bore and axially aligning the ball bearing 28 by engaging the outer race of the same, as is shown. The end 36 of the shaft 23 is threaded, and receives a nut member 37 and a suitable lock washer bearing against the inner race of the ball bearin g 28.

The central portion ill of the shaft is of reduced diameter where it passes through the central body portion 12, and has mounted thereon or integrally formed therewith inducer fins or blades 42 and impeller blades 43, the latter of which project within an annular recess 44 formed by the wall portion 45 of body 12 and the wall portion 46 of the body portion 2t The body portion 17 is recessed, as at 48, so as to be disposed in spaced relationship to the corresponding side face 49 of body portion 12 forming an inlet chamber Sit. The inlet chamber is communicated with the primary inlet chamber 51 by means of a series of axially extending circumferentially spaced bores 52. The wall portion of the body 12 is faired or rounded, as at 53, to provide a smooth inlet for the fluid entering through the inlet ducts 52 and the wall portion 46 of the body portion 2% is likewise faired or rounded to provide a smooth entry of fluid through the inlet 55. The main inlet for the pump is through the nipple portion 56 formed in the body 2%) providing an entrance passageway 57, as shown.

The upper extremity 59 of shaft 23 is of reduced diameter and is received in the hub db of a turbine wheel 61 and is affixed against rotation relative thereto either by keying or by splines, as desired. The turbine wheel 61 is fixed axially relative to the shaft end portion 59 by means of a suitable bolt 62 and the turbine wheel 61 itself is provided peripherally thereof with buckets or blades 63. The turbine wheel is housed between two body portions 64 and 65' secured together at their parting faces 65 by suitable fasteners, not shown, with the body portion 6% having formed therein an inlet passage or collector chamber 67 for the operating fiuid having at least one discharge nozzle passageway 63 therein directed to the bladed periphery of the turbine wheel d1 for driving the same in the well known and conventional manner. The bod portion 65 is provided with a centrally disposed bore "7t? providing an exhaust passage 71 for the operating fluid and an inlet 2 is provided leading to the collector chamber 67 of the turbine assemblage.

To hold the entire assemblage together, there are provided a series of studs 75 which are threaded at their lower extremities into the end piece 31 and which have threaded ends projecting through the body dd to receive nuts 74 disposed just below the turbine wheel 61. From the above description and a study of FIGURE 1 of the drawings, it Will be seen that an extremely compact and easily accessible construction is achieved. in initially assembling the component parts, the studs "75% are secured within the end plate 31 and then the body member Ztl is slipped over the studs into seated en agement with the end piece 31 whcreafter the shaft 23 and bearing 28 are fitted together within the end piece 31, the nut 37 secured and the end plug may also be secured at this point. The central body portion 12 is next fitted over the studs 75 and then the upper body portion 17, whereafter the ball bearing 26 is fitted in the counterbore 25 and the turbine body portion 64 fitted thereover and against the upper body piece 17. At this point, the nuts '74 are installed and tightened, which sandwiches all the body parts together with the exception of the body part 65 of the turbine assemblage. At this point, the turbine Wheel 61 is fitted and the bolt 62 secured, and lastly, the upper portion 65 of the turbine body is fitted to the lower body portion 64 thereof, completing the assembling of the device. By this construction, an extremely compact, light weight and yet high capacity direct driven turbo-pump is achieved. Both the turbine and the pump are single acting, but it is to be noted that for greatest efficiency, the pump is provided with dual inlets, one on either side of the impeller assemblage.

The construction of the inducer and impeller blades will be seen more clearly from a study of Fl-GURES 2 and 3. In these figures, it will be appreciated that the shaft portion 40 has a plate-like web Sllrigid therewith and extending radially therefrom upon which are mounted the impeller blades 43 previously mentioned with the periphery of the web between the impeller blades being scooped out, as at lid. The inducer blades or fins 42 are disposed on either side of the web bib and the impeller blades 43 likewise extend on either side thereof. For the purpose of discharging from the impeller chamber to the outer chamber 13 of the pump, there are provided in the body portion 12 a plurality of substantially tangentially extending discharge passages 52 leading from the impeller chamber and tapering outwar ly therefrom to discharge into the chamber 13.

As can be best seen in FIGURE 3, each of the impeller blades 43 is slightly arcuated and the inner edge 33 thereof is formed substantially as the leading edge of an airfoil. The inducer blades 42, on the other hand, extend substantially radially from the shaft portion as and are preferably formed equal in number to the number of impeller blades 43, although they extend radially along lines substantially midway between corresponding adjacent pairs of impeller blades 43.

Referring back to FIGURE 1 again, it will be seen that the inner edges 64 and 35 of the impeller blades are angled outwardly away from the inducer blades 42. Likewise, the inducer blades 42 are of generally semicircular configuration disposed substantially symmetrically on either side of the web portion 39. It has been found that by angling the edges 34 and 35 of the impeller blades, the tendency for the impeller blades themselves to create turbulence of the kind that leads to cavitation is substantially eliminated. When the pump is to be utilized with fluids containing abrasive materials, such as when used as a deep well pump, the leading edges of the impeller blades may be provided with a plating of tungsten carbide or similar material to withstand the abrasive action to which they will be subjected.

As can be seen in FIGURES 2 and 3, the inducer is of the radial type which is disposed in close adjacency to the entrance edges or inner edges of the impeller blades 43. The inducer is built in such a way that the fluid particles flowing in a region closer to the leading or inner edges of the impeller blades receive a gradually larger impetus from the inducer than do the particles flowing closer to the shaft portion 4 t) and which are hence caught or acted upon better by the outer extremities of the main impeller blades. This feature prevents the build-up of any air or gas void close to the center of the inducer I. On the other hand, the fluid particles leaving the inducer vanes have difierent velocities and follow different paths on their way toward the entrance of the main impeller. They will hit the leading edge of the main impeller vane under different angles of attack along the edge. Also, the angle of attack at one particular point of the vane edge will change with any capacity change due to the throttling effect which altered the capacity. For this reason, the entrance portions of the main impeller vanes or blades have the form of the leading edges of aircraft foils. An aircraft foil shape has to be chosen which in the range of operational flow of velocities with a corresponding range of angles of attack will not show separation of the boundary layer or effect cavitation. As shown in FIG- URE 3, the dotted lines indicate the liquid flow relative to the impeller; as long as liquid flows within the inducer, the flow pattern is radial, but when leaving the inducer, the flow direction will bend backwards relative to the impeller, since the fluid particles reach larger wheel radii and with higher circumferential speed without being accelerated by any vane. When the particles finally hit the main impeller vane, the fluid path will have its largest radius of curvature and the leading edge of the impeller blades must provide shock-free entrance so as to prevent boundary separation or cavitation. The subsequent curvature of the main vane or impeller vanes can be chosen according to the pump capacity requirements, since after having once impinged against the leading edge, the particles will not be as sensitive to sudden directional or velocity changes as they are in the area where they initially strike or enter the impeller assemblage.

Referring now to FIGURE 4, the lines marked 4, 6, 8 and 10, respectively, represent points on the outer edge of the inducer blades which are spaced at increasingly greater radial distances from the pump shaft, and the relative motion of the water particles leaving these points relative to the moving impeller. FIGURE 4 clearly illustrates that the energy imparted to the water particles increases as their point of leaving the inducer blades is displaced more and more radially from the shaft. Consequently, in order to prevent boundary separation and cavitation, and to enhance the capacity and efiiciency of the pump, it is preferred that the impeller blades at their 'eading edges be progressively flattened in their angle of attack relative to the inducer blades. Such an arrangement is clearly illustrated in FIGURES 5 and 6 of the drawings. In this instance, the inducer blades are indicated by reference characters 1% and 101, representing portions of the same inducer blade on opposite sides of the web 1&2 upon which the impeller blades 163 are mounted. The portions 194 of the impeller blades which are adjacent the web 102 have a relatively steep angle of attack relative to the inducer blades, Whereas the leading edge 1% of such impeller blades is progressively flattened in its angle of attack relative to the inducer blades progressively outwardly from the web 102, see particularly FIGURE 5.

A further modification is illustrated in FIGURES 7 and 8, wherein the same general configuration of impeller blades 110 is utilized as is described in conjunction with FIGURES 5 and 6, but in the modification of FIGURES 7 and 8, the inducer blades 111 and 112, on opposite sides of the web M3, are angled laterally with respect to the axis of the shaft to which they are affixed, as indicated by reference character 114, Whereas the main body portion of these inducer blades extends axially of such shaft.

A still further modification is illustrated in FIGURES 10 and 11, wherein it will be seen that the impeller blades 120 are similar to those described in conjunction with FIGURES 5 and 7, and :wherein the inducer blades 121 and 122, on opposite sides of the web 123, extend axially of the shaft upon :which they are mounted and extend radially thereof, similar to the configuration of the inducer blades 161 in FIGURE 5. However, shrouds 124- and 125 are disposed between adjacent inducer blades 12.1 and 122, respectively, so as to provide a channel 126 of decreasing axial cross-sectional area radially outwardly of the mounting shaft so as to channel the fluid to receive the greatest impetus from the inducer blade and direct the fluid toward those portions of the impeller blades which have the steepest angle of attack relative to the inducer blades. This has the effect of very materially enhancing the flow characteristics of the purnpermitting of its greater angular velocity and hence of its capacity.

What is claimed is:

1. In 21 directly driven, high speed centrifugal pump, a rotatable shaft, a pump housing surrounding said shaft and providing an annular impeller blade-receiving chamber therein, a series of circumferentially spaced, axially extending generally semicircular inducer blades fixed to said shaft in radial disposition relative thereto, a web fixed to said shaft radially thereof and about which said inducer blades are substantially symmetrical, a plurality of impeller blades fixed to said web generally radially with respect to said shaft and operating within said chamher, said chamber having peripherally disposed, circumferentially spaced disc-barge openings, and the inner sides of said impeller blades being angled from said web outwardly relative to the axis of said shaft, each of said inducer blades having opposite end edge portions thereof directed laterally substantially transversely of the axis of said shaft.

2. In a directly driven, high speed centrifugal pump, a rotatable shaft, a pump housing surrounding said shaft and providing an annular impeller blade-receiving chamber therein, a series of circurnferentially spaced, axially extending generally semicircular inducer blades fixed to said shaft in radial disposition relative thereto, a web fixed to said shaft radially thereof and about which said inducer blades are substantially symmetrical, a plurality of impeller blades fixed to said web generally radially with respect to said shaft and operating Within said chamber, said chamber having peripherally disposed, circumferentially spaced discharge openings, and the inner sides of said impeller blades being angled from said web out- Wardly relative to the axis of said shaft, each of said inducer blades having opposite end edge portions thereof directed laterally substantially transversely of the axis of said shaft, and the inner edges of said impeller blades closest to said shaft being increasingly angled laterally to present an increasingly flatter angle of attack relative to said inducer blades progressively from said web toward the outer extremities of said impeller blades remote from said web.

References Cited in the file of this patent UNITED STATES PATENTS 1,075,300 Moss Oct. 7, 1913 1,337,659 Kerr Apr. 20, 1920 1,810,297 Schleyer June 16, 1931 2,361,750 D-insmore et a1 Oct. 31, 1944 2,379,133 Curtis June 26, 1945 2,700,344 Sohellens Jan. 25, 1955 2,701,528 Angell Feb. 8, 1955 2,766,697 .Tudd Oct. 16, 1956 2,819,838 Warner Ian. 14, 1958 2,896,543 Ogles July 28, 1959 2,991,604 Denbo et al. July 4, 19 61 FOREIGN PATENTS 725,909 Great Britain Mar. 9, 1955 

1. IN A DIRECTLY DRIVEN, HIGH SPEED CENTRIFUGAL PUMP, A ROTATABLE SHAFT, A PUMP HOUSING SURROUNDING SAID SHAFT AND PROVIDING AN ANNULAR IMPELLER BLADE-RECEIVING CHAMBER THEREIN, A SERIES OF CIRCUMFERENTIALLY SPACED, AXIALLY EXTENDING GENERALLY SEMICIRCULAR INDUCER BLADES FIXED TO SAID SHAFT IN RADIAL DISPOSITION RELATIVE THERETO, A WEB FIXED TO SAID SHAFT RADIALLY THEREOF AND ABOUT WHICH SAID INDUCER BLADES ARE SUBSTANTIALLY SYMMETRICAL, A PLURALITY OF IMPELLER BLADES FIXED TO SAID WEB GENERALLY RADIALLY WITH 